Home-Made IEMs
Sep 18, 2020 at 10:08 AM Post #11,566 of 13,624
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Thanks @Bassiklee
I suppose what I'm curious about is what makes the Bellsing 6 so special? Could I just source any DTEC and 2 TWFK's and tune them together to accomplish the same result?


If you don't have a coupler, how have you been measuring your builds to this point?
What made BZ6 special is: The ease of assembly, also how Bellsing manage to cross those 3 kind of driver at their best frequency.

@dhruvmeena96 doesnt even need coupler, his pen & paper calculation is spot on. If he says a build is gonna be harman, it will measure exactly harman on coupler.
 
Sep 18, 2020 at 12:51 PM Post #11,568 of 13,624

shdh

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@dhruvmeena96 doesnt even need coupler, his pen & paper calculation is spot on. If he says a build is gonna be harman, it will measure exactly harman on coupler.
I'm not doubting his abilities or knowledge, I've read many of his posts. But I'm sure he agrees, a scientific/engineering approach requires proper measurements. Measurements also help aid in better decision making and documentation of designs. That's just my perspective though. :ksc75smile:
 
Sep 18, 2020 at 11:19 PM Post #11,569 of 13,624

johnchpark

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ED29689 ED26805 DWFK31785.png


image0.jpg


Hi, so i tried wiring and testing some of my drivers, and my fullrange drivers (ED29689, ED268905, DWFK31785) all came out looking like this. Doesn't look like the data sheets.
Just wired directly + to +, - to -. 15mm Tube.
My other woofers and tweeters graph correctly.
Is there something I'm missing?


UPDATE:
It was my coupler.
I have two devices. Changed them out, and problem fixed.

image1.jpg
image0 (1).jpg
 
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Sep 19, 2020 at 3:07 AM Post #11,570 of 13,624

shdh

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ED29689 ED26805 DWFK31785.png

image0.jpg

Hi, so i tried wiring and testing some of my drivers, and my fullrange drivers (ED29689, ED268905, DWFK31785) all came out looking like this. Doesn't look like the data sheets.
Just wired directly + to +, - to -. 15mm Tube.
My other woofers and tweeters graph correctly.
Is there something I'm missing?


UPDATE:
It was my coupler.
I have two devices. Changed them out, and problem fixed.

image1.jpgimage0 (1).jpg
Nice, I also use REW to measure. Where did you get your coupler from?

I was thinking there should be a database of collected measurements for different drivers, similar to Crinacle's graph tool. I know there are a number of drivers for which you cannot find the actual frequency response curve. If there is interest I could put together such a tool.
 
Sep 19, 2020 at 3:47 AM Post #11,571 of 13,624
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Nice, I also use REW to measure. Where did you get your coupler from?

I was thinking there should be a database of collected measurements for different drivers, similar to Crinacle's graph tool. I know there are a number of drivers for which you cannot find the actual frequency response curve. If there is interest I could put together such a tool.
Im interested if u gonna make one. I got similar 711 coupler as the post above, i can help a bit.

But we should start by standarizing the measuring process & parameter first.
 
Sep 19, 2020 at 1:05 PM Post #11,572 of 13,624

Arturo Sallas

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Hello guys. I have a few questions I´d like to ask.

I abandoned my IEM project a while ago to take care of other personal projects, but with this quarantine I took it out of the drawer and I´m back. I did a full clear model for myself and a blue and gold for my brother who is a musician, 4 drivers on both models. So far I´ve done my negatives with Gelatine + Glycerine but I struggled a bit because the gelatine is not fully clear, is a bit yellowish, so I had some poorly cured shells that I had to trash. I want to get the Dreve Fotosil 2 part silicone, but I´m not sure if it´s possible to mixwithout the machine that dreve sells. Has any of you tried mixing manually? Are bubbles a problem? I´m sure this has been mentioned before, but I couldn´t find the post.

Regards
IMG_4217.jpgIMG_4431.jpg
 

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Sep 19, 2020 at 2:24 PM Post #11,573 of 13,624

shdh

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But we should start by standarizing the measuring process & parameter first.
One thing we could do is use a common driver as a point of reference. For example, anyone that wants to contribute to the database would need to have a measurement of TWFK-30017 unfiltered with a 10mm long 1mm inner diameter tube that matches the databases existing measurements within a margin of error.

I think Banbeu has a good measuring procedure:
  1. Using white noise to reach 85dB(+-1.0dB) on Left channel. Maintaining same volume step in right channel
  2. Resonance peaks are kept as close as 8.000Hz as possible (Consider this as a guidelines, the insertion peak might varies on some IEM like ER4S where I intentionally left a >10kHz insertion to emulate a deep insertion)
  3. Microphone are calibrated using provided file from manufacturer
  4. Soundcards are calibrated using either manufacturer files (if available) or by running a sweep with an external loopback setup using REW
  5. Sine sweep are ran with Length = 256k and Sample rate of 48kHz with 1 repetitions
  6. dB Scale: 60 - 110dB
We could also standardize the tube length and inner diameter to match a standard. Or have a variety of tube length measurements specified, along with any applied filters.
 
Sep 19, 2020 at 2:38 PM Post #11,574 of 13,624

Bassiklee

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Fotosil is not perfectly clear either. Apparently Klarsil is. I have a Dosper, only because I got it for ridiculously cheap. Having used the 2L kit of Fotosil, I'm not sure if I'd bother with it again. It's not that much better than hydrocolloid, and it's pretty expensive. I figure about $4 a pair of investments.
 
Sep 20, 2020 at 9:42 AM Post #11,575 of 13,624

johnchpark

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I'm using some Taobao 711 coupler, but it measures relatively close to Crin's graphs, so pretty reliable I think.

Question,
I set up my crossovers, and I can measure each driver separately to confirm that it's the shape I want.
But when I try to stick the tubes together in a makeshift "nozzle" (I made a tube shaped cylinder with Egger resin and drilled holes to stick the tubes in), the mid and bass drivers don't seem to graph.
Is it not possible to graph the FR without putting everything in a closed shell?

Individual driver measurements:

separately.png


Combined Measurement:

combined.png


F024F7EF-D0A4-49A0-BF2B-18424D840E79.jpeg


5A56202B-C755-4165-830E-5227088A7C63.jpeg
 
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Sep 20, 2020 at 9:56 AM Post #11,576 of 13,624

musmecca

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I'm using some Taobao 711 coupler, but it measures relatively close to Crin's graphs, so pretty reliable I think.

Question,
I set up my crossovers, and I can measure each driver separately to confirm that it's the shape I want.
But when I try to stick the tubes together in a makeshift "nozzle" (I made a tube shaped cylinder with Egger resin and drilled holes to stick the tubes in), the mid and bass drivers don't seem to graph.
Is it not possible to graph the FR without putting everything in a closed shell?

Individual driver measurements:

separately.png

Combined Measurement:

combined.png

F024F7EF-D0A4-49A0-BF2B-18424D840E79.jpeg

5A56202B-C755-4165-830E-5227088A7C63.jpeg
Most people will use bluetac or some other soft moldable material to seal the tubes in place COMPLETELY. If you have any leaks, it willl show up particularly in the loss of low frequency which is what you are expereincing....they have to be completely sealed. Once it is sealed, any variations can usually be attributed to phase cancellation/driver interaction issues. Just because they look great individually doesn't mean they will behave nicely once together, but it's a start.
 
Sep 20, 2020 at 9:58 AM Post #11,577 of 13,624

johnchpark

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Most people will use bluetac or some other soft moldable material to seal the tubes in place COMPLETELY. If you have any leaks, it willl show up particularly in the loss of low frequency which is what you are expereincing....they have to be completely sealed. Once it is sealed, any variations can usually be attributed to phase cancellation/driver interaction issues. Just because they look great individually doesn't mean they will behave nicely once together, but it's a start.

So it doesn't have to be in a sealed shell, but the tubes should all be sealed with the coupler completely?

Thanks, I'll give it another try.
 
Sep 20, 2020 at 11:07 AM Post #11,578 of 13,624

mattmatt

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One thing we could do is use a common driver as a point of reference. For example, anyone that wants to contribute to the database would need to have a measurement of TWFK-30017 unfiltered with a 10mm long 1mm inner diameter tube that matches the databases existing measurements within a margin of error.

I think Banbeu has a good measuring procedure:
  1. Using white noise to reach 85dB(+-1.0dB) on Left channel. Maintaining same volume step in right channel
  2. Resonance peaks are kept as close as 8.000Hz as possible (Consider this as a guidelines, the insertion peak might varies on some IEM like ER4S where I intentionally left a >10kHz insertion to emulate a deep insertion)
  3. Microphone are calibrated using provided file from manufacturer
  4. Soundcards are calibrated using either manufacturer files (if available) or by running a sweep with an external loopback setup using REW
  5. Sine sweep are ran with Length = 256k and Sample rate of 48kHz with 1 repetitions
  6. dB Scale: 60 - 110dB
We could also standardize the tube length and inner diameter to match a standard. Or have a variety of tube length measurements specified, along with any applied filters.
If you guys want to have a really standardized measurements across a specified group, one can measure a single ba with a 0.4cc coupler, BA directly place in the coupler, export as CSV file. Share the CSV file.

Other people from the group should measure the same BA and same parameters. Export his measurement as CVS. From this CSV, we can open it via excel. The values can be deducted and copy-pasted to a notepad as saved as .mic file. import it as a calibration file.

That way, a group will have the same measurements regardless of the mic and soundcard differences.

I managed to do this to one of my mics with improper response.

It will be great if someone can do this with a standard and original IEC coupler but I think the knockoffs have a near perfect response.
 
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Sep 20, 2020 at 3:35 PM Post #11,580 of 13,624
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I'm using some Taobao 711 coupler, but it measures relatively close to Crin's graphs, so pretty reliable I think.

Question,
I set up my crossovers, and I can measure each driver separately to confirm that it's the shape I want.
But when I try to stick the tubes together in a makeshift "nozzle" (I made a tube shaped cylinder with Egger resin and drilled holes to stick the tubes in), the mid and bass drivers don't seem to graph.
Is it not possible to graph the FR without putting everything in a closed shell?

Individual driver measurements:

separately.png

Combined Measurement:

combined.png



Yo bro, we're using similar method 🤣, hi five. Its even look very similar, lol. Mine's 3d printed.

Bass rolloff, it might be because the adapter has some leak, i put masking tape on mine, so i can fit it tightly into the coupler.

There will be some weird dip somewhere, due to our not-so-compliant adapter, dont worry about it.

About ur combined graph mid, check the phase, then try to match phase of all driver by tweaking with the polarity. There's some phase cancellation i guess.
 

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